Right off the bat, I have to warn you: Marvel Heroic Roleplaying is a mashup of different RPG philosophies and may not be what you're expecting from a super-hero RPG. If you give it a chance, if you accept that not all of it may necessarily flow down traditional RPG design paths, I think that you'll find it's an excellent RPG.
It uses Cortex Plus, which -- as anyone whose even leafed through another Cortex Plus rulebook can tell you -- doesn't necessarily guarantee the exact same ruleset. This variant still creates dice pools, but the sources of these dice pools (Affiliations, Distinctions, Power Sets, and Specialities) are different enough from the Smallville version to claim that it's a different game altogether.
I do like the Affiliations (which differentiate character power levels when operating as part of a team, as a buddy, or solo) and the Distinctions (which give both bonuses and "penalties" based on character "tags" or "schticks") a lot because of the narrative / comic book feel they give the game.
I like the Power Sets with some reservations. While the Power Sets (with their related SFX, Stunts, and Limits) do allow for very broad, yet customizable abilities that can fit on one page, the absence of a coherent point-based approach really throws me off when trying to determine relative power levels. They also may pose problems for GMs and Players with less solid character concepts and more rules lawyer-oriented philosophies.
The Specialties are a nice way to cover skill groups quickly, in pretty much the same fast-and-loose way that comics tends to handle skills. I wish that there was a little bit more gradation in the skill levels though.
Of course, it does mean that Character Creation can be very fast, and can be tweaked as the game goes along.
As far as task resolution, GMing, and scene / adventure / campaign rules go -- it's very much got a narrativist / indie feel (game milestones that grant XP that you can spend to tweak the game, several mechanics that feel very much like Fate), but with just enough crunch to pencil in justifiable rankings on the abilities of a given character.
The art is fantastic, and -- since most of it was taken from comics in the past decade -- it has a very modern feel to it as well.
The mini-event that comes with the game, and the characters with ready stats, are all taken from the New Avengers storyline that preceded the whole Civil War, Dark Reign, and Siege storylines.
Overall, it's a fantastic RPG that somehow manages to grant that feeling of playing in a modern Marvel comic book, somehow gives mechanics to the somewhat elastic power levels found in their pages, and somehow allows the players to recreate the narrative ebb and flow of adventure and drama in the genre.
Most important -- it's an RPG that makes me want to play! Avengers Assemble!
I guess the most difficult thing for me is dealing with the narrative mechanics. It really twists my mind in non-traditional directions, much like the Fate rulesets always have. In fact, I'm more comfortable with the World of Darkness rules, which I consider more traditional, than these types of rules. But with Marvel Heroic Roleplaying, I have a better feel and understanding of why they might work in emulating the genre.